A few days back I spoke with a gentleman at a cruise event who claimed to work at the St Louis plant in the late 1960's to the late 1970's. I asked what he did on the production line and what it was like working on the muscle cars of the day. The topic of spoilers came up in the conversation and he stated that the factory never installed spoilers on any cars in the b body line. Is there any truth to this or was he mistaken?

Was an option for 70 and 71. Was on the build sheet and data tag so was factory installed. Did he do a lot of acid back then?

Some cars were shipped with hub caps in the trunk and antenna masts removed for shipping, then later installed as part of dealer prep. Were spoilers done at the dealership or at the factory? Sorry I didn't clarify in my original post, but that's what I meant to say. the man said he installed front to rear wiring and tail and rear marker lights during his time at the plant. I don't know where that is as far as the assembly process goes, but maybe he was never in the area when those options were installed.

TA and AAR front chin spoilers were not installed at factory.. were shipped in the trunk to intended dealership with instructions and hardware.
You are inquiring about front B-body spoilers and I would assume they were shipped the same way.
At issue was the clearance for loading...chin, front spoilers would catch going on and off the transporter.

1970 B-body factory "J81" rear spoilers are uncommon

of the 158,000+ cars down the St. Louis line for model year 1970 ….
"IF" a handful per day (of ~800) came down the line & were installed after his station would he have noticed & remembered the holes in the decklid?

this is an early-May '70 factory St. Louis built RM21 with J81, that I owned in the late-'80s/early-'90s